Advaxis sees encouraging results for immuno-oncology treatment in dogs with bone cancer

Nicola Mason, principal investigator on the trial at the University of Pennsylvania School of Veterinary Medicine

A growing number of biotechnology companies are recruiting pet dogs with cancer to help test new therapies that might ultimately help people with cancer. One of those companies, Princeton, NJ-based Advaxis ($ADXS), has seen such encouraging results in dogs for one of its drug candidates, ADXS-cHER2, that it has embarked on a parallel development program: studying the drug in pediatric osteosarcoma, while partnering with Aratana Therapeutics ($PETX) to move the drug forward in canine osteosarcoma.

On Thursday, Advaxis announced the latest milestone in that effort--positive results from a Phase I trial of ADXS-cHER2 in 18 dogs with osteosarcoma treated at the University of Pennsylvania School of Veterinary Medicine. The drug is a therapeutic cancer vaccine that's designed to spark an immunological response against HER2, a protein that is overexpressed in certain solid tumors, including osteosarcoma. During the trial, 50% of the dogs who received the treatment generated clear immune responses, according to an Advaxis press release.

Even more impressive was the survival data. All the dogs in the trial received the standard of care for bone cancer, which is amputation and a traditional chemotherapy treatment. The median survival time for the dogs that just received that therapy without the experimental vaccine was 316 days. But two-thirds of the dogs that were treated with Advaxis's drug are still alive, including three who have lived longer than two years and are still cancer-free, says Penn's Nicola Mason, who is the principal investigator on the trial. Therefore the median survival time has not been able to be calculated.

Mason believes the trial demonstrates the potential value of immunotherapy in treating bone cancer, which has an unfortunate tendency to metastasize, in both dogs and children, even after the primary tumor is removed. "Osteosarcoma is becoming one of those tumors that we think is in fact immune-responsive," Mason told FierceAnimalHealth. "The length of time some of these dogs are [surviving] is really incredibly prolonged." Side effects seem to be minimal, she added.

Advaxis is currently planning clinical trials of ADXS-cHER2 in children with osteosarcoma, and the company plans to file to the FDA for approval to test the vaccine in other tumors that express HER2.

ADXS-cHER2 is one of three experimental immunotherapeutics that Advaxis has licensed to Aratana for development in veterinary medicine. In addition to the Aratana deal, Advaxis has formed several other partnerships to move its cancer vaccines forward, including a deal with Merck ($MRK) to test a combo of the cancer vaccine ADXS-PSA and Merck's checkpoint inhibitor pembrolizumab, and a pact with AstraZeneca ($AZN) to test the former's MEDI4736 antibody with ADXS-HPV in HPV-related cancers.

As for ADXS-cHER2 on the veterinary front, further studies are being planned in dogs, Mason says--an effort that she hopes will provide veterinarians with a new tool against osteosarcoma. "This disease in dogs seems to be increasing in incidence now. We estimate there are going to be at least 50,000 dogs a year with it," Mason says. "Many of these are large and giant-breed dogs, a number of which are service dogs. It would make a huge impact being able to keep these dogs in the family, and keep them alive with a good quality of life."

- here's the press release